Question

Question: Uridine monophosphate (UMP) is one of the four nucleotides that compose RNA, the nucleic acid that translates the genetic information of DNA into proteins needed by cells for proper function and development. A key step in the synthesis of UMP is the reaction of A with B to form C, which is then converted to UMP in one step. Draw a stepwise mechanism for this S_N1 reaction.

Short answer

ANSWER

Resonating structures

Nucleophilic attack of the phosphate group

Formation of the compound C

Step-by-step solution

Synthesis of Uridine monophosphate by the cells

UMP is a monomer in RNA which consists of a pentose sugar ribose, the phosphate group, and the uracil as a nucleobase.

It is one of the four nucleotides which are the building blocks of RNA.

The synthesis of the UMP takes place by the S_N1 mechanism. The pentose sugar ribose and uracil, which is a nucleobase, react to produce the UMP.

The stepwise reaction for the synthesis of UMP

The synthesis of UMP takes place in the following steps:

The first step is the solvolysis, in which the ^-O-PP group is removed to form the resonance stabilized carbocation as shown in the following structure:

Resonating structures

The next step is the nucleophilic attack of the phosphate group on the carbocation intermediate, as shown below:

Nucleophilic attack of the phosphate group

In the final step, there is an abstraction of the proton by the ^-O-PP to produce the final product.

Formation of the compound C